What is the required inlet pressure to be indicated on the sign at the fire department connection if the system demand exceeds a certain threshold?

The correct answer is 150 PSI, which aligns with the requirements outlined in NFPA 24 regarding the signage for fire department connections. This elevation in inlet pressure indicates that the system is designed to supply adequate water flow and pressure to meet firefighting demands, particularly in scenarios where the system demand exceeds thresholds set for effective operation.

The significance of having 150 PSI displayed is that it serves as a critical reference for firefighters, enabling them to assess whether the pressure available at the fire department connection is sufficient for their operational needs. This information can influence their approach to combating a fire, ensuring that they have the necessary resources close at hand. By adhering to this pressure requirement, the installation reflects the standard practices meant to optimize the performance of private fire service mains and ensure they are effective during emergencies.